Allahumma inni astakhiruka bi ‘ilmik, wa astaqdiruka bi qudratik, wa as’aluka min fadlikal-‘adhim, fa innaka taqdiru wa la aqdir, wa ta‘lamu wa la a‘lam, wa anta ‘allamul-ghuyub. Allahumma in kunta ta‘lamu anna hadhal-amra khayrun li fi dini wa ma‘ashi wa ‘aqibati amri faqdurhu li wa yassirhu li thumma barik li fih. Wa in kunta ta‘lamu anna hadhal-amra sharrun li fi dini wa ma‘ashi wa ‘aqibati amri fasrifhu ‘anni wasrifni ‘anh, waqdur liyal-khayra haythu kana thumma ardini bih.
O Allah, I seek Your guidance through Your knowledge, and I seek ability through Your power, and I ask You from Your immense bounty. For You are able and I am not; You know and I do not; and You are the Knower of the unseen. O Allah, if You know that this matter is good for me in my religion, my livelihood and the outcome of my affairs, then decree it for me, make it easy for me, and bless me in it. And if You know that this matter is bad for me in my religion, my livelihood and the outcome of my affairs, then turn it away from me and turn me away from it, and decree for me what is good wherever it may be, and make me content with it.
Pray two voluntary rak‘ahs (not the obligatory prayer), then say this dua, naming your matter where it says "this matter".